Production of lubricating oils



April 2, 1957 c. H. wATKlNs Erm.. 2,787,582

PRODUCTION OF' LUBRIATING OILSv rFiled April 12, i955 United StatesPatent I O PRODUCTION OF LUBRICATING OILS Charles H. Watkins, WesternSprings, and Armand J. de Rosset, Clarendon Hills, Ill., assiguors to'Universal Oil Products Company, Des Plaines, Ill., a corporation ofDelaware Appncanon'nprn 12, 195s,..seria1No. 500,732

`s claims. (ci. 196'49).

This invention relates to 'a process for the preparation of lubricatingoil and in particular relates toa process for the conversion of higherboiling petroleum stocks to lubricating oils and, to improve virginlubricating oil fractions. .y

Iri recent years -there has been. adiminishing demand f orheavierpetroleuin'fractions which -boilin the fuel oil range and heavier and atthe same time the use of heavy lubricating oils Ihas diminished.Refiners of lubricating oils have therefore found that therepislinsuiiicient virgin lubricating oil in the boiling range desired, thatis the lighter lubricating oil boiling range, to satisfy the demands,while at the same time a problem has been created in profitablydisposing of the heavier oils. The desirable lubricating oils are thoseboiling in the range of from about 600 F. to about 950 F. The bestlubricating oilsl are composed of paratiinic and naphthenic hydrocarbonspreferably containing an `abundance of isomeric molecules sothat themelting point is low yand the viscosity is low. Tjhese lubricating oilscontain waxes which are long, straight chain hydrocarbons and thesewaxes are in solution or suspension inthe lubricating oil and must beremoved therefrom lbefore the oil is suitable for lubricating. The oilfractions varcfdewaxed by many methods, probably the most successful of.which comprises'mixing the entire oil fraction with a suitable solventsuch as -a mixture of toluene, benzene, and acetone, cooling untilthewax precipitates and then iiltering the wax from the mixture,followed by separation of the solvent from the oil. The presence of waxin the original oil fraction, although an impurity, is not undesirablesince Wax is an extremely valuable by-product whichin many cases isworth to the reiiner as' much as the oil from which it was -rhsneavieroii-sboiling above. 90o?? F., that isl ons heavier thanthesdesirablezlight lubricating oil, will have roughly the same chemicalcharacteristics as ithelubri` eatingl oilsince the two fractions are`obtained from the same stock, h owever,the molecules in lthe heavieroil will 'be larger homologs of those in the lighter stock. The heavieroil, following removal of the ldistillate lubrieating oil is calledcylinder stock, which may be dewaxed and deresined afterwhich it isknown as Bright stock which is useful for 'blending with dewaxed lighteroils to form heavier grades of lubricating oil. When not used forblending, cylinder stocks and Bright stocks may serve as a portion ofthe charge or starting'material for this process as hereinafterdescribed in greater detail. These heavier ymaterials are hydrogendeficient relative to the desirable 'lubricating oil fraction andltherefore, in order to be -converted into suitable lubricating oils,must be hydr-ogenatd. Other stocks which may be used .as a portion ofthe beginning material in this process are heavier fractions from othercrude's and cycle oils which may boil higher than the lubricating oil orpartly in the boiling range of lubricating oil but which are unsuitableas lubricating "oil,`

l a light lubricating oil fraction.

;Although a comparison of the characteristics of the starting materialand the ultimately desired material from -this process would suggest ahydrocracking operation, it has been found that large yields oflubricating oil cannot be obtained by hydrocracking. When ahydrocracking operation is started, lube oil is obtained, however, therecycling of material boiling higher than 950 F. from the syntheticcrude or total eluent from the hydrocrack-` ing process, causes thedegree of unsaturation of the combined feed to the process tocontinuously increase. Unsaturation of the charge stock is a seriousdetriment to this process inasmuch as unsaturated material in thisboiling range, that is above 900 F., forms excessive quantities of cokewhen heated Iand therefore requires more extensive regeneration with theresultant ineiciency of the process and loss of material. For example,when the process is effected in a fixed bed there are only brief.

reaction cycles between periods of regeneration.

Another objection to hydrocracking is that the heretofore mentionedvaluableV wax material is destroyed since the long, straight chainmolecules of wax are Vulnerable to cracking and therefore the syntheticcrude contains little. tion arel experienced when conventionalhydrocracking is used as for example the production of increased quan-vtities of gasoline at the expense of the yield of lubricating oil andwax.

Our invention provides a specific process for the production of asuperior grade of lubricating oil from the charge stock which processmay 'be operated to convert the charge stock to extinction withoutserious Coking difficulties and which process not only does Vnot destroythe valuable wax product but actually increases the amount and qualityof wax produced.

The Bright stock prepared as hereinbefore described may find use as ablending stock to increase the weight of Therefore when the process ofthis invention is operated to produce for example, S. A. E. No.. 10grade lubricating oil and a certain amount of No. 20 or No. 30 grade isalso desired, these heavier grades can be produced by blending theproper amounts of Bright stock with the product from the process.=Therefore, it is frequently desirable, especially for lubricating oil tobe consumed in the warmer climates and the Warmer months, to lhaveBright stock available for Iblending.

As hereinbefore described it is very undesirable to have unsaturation inthe heavier stock from the synthetic crude from ythis process since itcauses fouling of the catalyst,

heaters and other parts of the plant, however, it' is also undesirableto have unsaturation in the portion of the synthetic crude that is notrecycled. The desired light lubricating oil produced in this process isnot recycled to the reaction and therefore not again subjected toreaction conditions, however, this fraction should also be saturated andstable since this increases its desirability as'a lubricating oil.Although isomeric molecules are desirable in lubricants, unsaturatedmolecules are not and hence a light lubricating oil fraction from thisprocess or from the virgin crude may be improved by hydrogenation whichsaturates both olefinic compounds to produce par.; ains vand-aromaticcompounds to produce naphthenes,

both reactions substantially improving the lubricating qualitiesy of thestock upon which they were performed. The ysaturation reactions improvethe heavier Bright stock lsimilarly to the improvement effected on thelighter stocks and therefore hydrogenation steps on heavier stocks laredesirable when they are used either as a blending stock in lubricatingoil or as a recycle stock to the process.

,It is therefore an object of this invention to produce aj j saturatedlight lubricating oil fraction vfromv a substan-l Other disadvantages ofyield and product distribu-y tially hydrocarbon material and to obtainhigh yields of product by recycling the unreacted material to theconversion zone.

In one embodiment this invention provides a method for producinglubricating oil which comprises -separating a petroleum material into atleast a light lubricating oil fraction and a bottoms fraction, passingat least a portion of said bottoms fraction into contact with a catalystcomprising a compound containing a metal from the left hand column ofgroup VI and an iron group component at a temperature of from about 750F. to about 850 F. and a pressure in excess of about 100 p. s. i.,separating the resultant converted material into a synthetic lightlubricating oil fraction and a synthetic bottoms fraction, returning atleast a portion of the latter into contact with said catalyst,commingling the resultant synthetic light lubricating oil fraction withthe aforesaid light lubricating oil fraction and passing the resultantmixture into contact with a hydrogenating catalyst under hydrogenatingconditions and dewaxing the resultant hydrogenated light lubricating oilto produce the 4aforesaid lubricating oil.

In a preferred embodiment of this invention the catalytic materialcomprising group VI and group VIII metal components is disposed on acarrier material having non-cracking characteristics and the destructivehydrogenation process is elected with regeneration of the catalyticmaterial.

As hereinbefore stated the charge to this process is separated into atleast a light lubricating oil fraction and a bottoms fraction. Thecharge may comprise a total crude oil and the fractionation may beelected in several fractionators wherein various fractions are removedor in a single fractionator wherein the lighter material is taken fromthe top of the column, and the lubricating oil fraction is taken as aside cut while the bottoms form the charge to the destructivehydrogenation zone. The charge to this process may comprise a distillateafter gasoline, kerosene, and lighter material are removed or it may bea synthetic crude from a thermal cracking or catalytic crackingoperation. The charge may also cornprjise a blend of synthetic crude andnatural or virgin crude o il or it may consist of or be blends of any ofthese alone or in combination. The other sources of charge to thisprocess may include the product from destructive hydrogenation of shale,coal, wood, etc. Aboutl the only limitations upon the charge stock ofthis invention 'are that Vit must beV substantially hydrocarbon innature, that is having a predominant number of moleculeshydrocarbonaceous although they may be commingled with sulfnrfcontainingmolecules such as mercaptans, thiophencs etc. or nitrogen-containingmolecules or oxygenfcontaining molecules which will gener-V ally beconsidered impurities in the total stock. It is preferred that thecharge to the unit be parairlnic4 in na-. ture rather than asphalticinasmuch as paranic charges contain substantially smaller quantities ofaromatic and condensed ring polynuclear compounds which form-asphaltenes and precipitate out of solution to form black carbonaceousdeposits upon heater tubes and catalytic particles. When asphalticstocks are employed in the process of this invention it is preferredthat they be deasphalted by any suitable method lprior to introductioninto the unit. Suitable methods of deasphalting and deresining stockswill be discussed in greater detail hereinafter.

As hereinbefore stated, the charge stock to the process. of thisinvention must be fractionated into at least a light lubricating oilfraction and a bottoms fraction. The fractionation zone of thisinvention is contemplated as being ya conventional fractionatorcontaining suitable means. for effecting separation of material byvirtue of Vdilference in boiling point. The fractionationzone willcontain some means of etecting intimate contact between a risingmolybdenum-iron, and other variations.

vapor stream and a descend-ing liquid stream and may contain forexample, such contact inducing devices as bubble trays, perforateddecks, packing material, ctc. The object of the fractionation is toseparate material already boiling in the light lubricating oil rangefrom heavier material so that only the material requiring treatment needbe treated.

The bottoms material from the fractionation zone is roughly analogous tothe light lubricating oil desired, however, the Vmolecules in thismaterial are generally heavier homologs than those in the lighterfractions. The bottoms will generally boil above 900 F Iand preferablyabove about 950 F. and `will usually comprise heavy paranic material andwaxes. It the bottoms fraction from the fractionation zone is highlyaromatic it will preferably be treated to precipitate these aromatics asasphalt or asphaltenes after which treatment it is known as cylinderstock and when further treated to be dewaxed and deresined it is calledBright stock, the characteristics o f which were hereinbefore described.

The heavy material is passed to the destructive hydrogenation zone whereit is contacted with the heretofore mentioned catalyst at reactionconditions.

As hereinbefore stated, the catalyst to be used in the process of thisinvention comprises a metal component from the left hand column of groupVl and an iron group metal component. These components are preferablydisposed upon a base having no cracking activity. The preferred metalcomponents are cobalt and molybdenum, however, the other members of theindicated groups may be used with success in such combinations aschromium-cobalt, tungsten-cobalt, chromium-nickel, The metal com :pimentmay be in the form of the metal or in the form ol its oxide, sullide,halide or other compound and usually when the charge stock containscombined sulfur the metal components will be at least partially in theform or" their suldes during processing. The metals may be compositedwith the non-cracking base when such is used by any of the well knownmethods such as impregnation from solutions of the soluble salt of themetals either concurrently or successively followed by precipitation bytreatment with precipitating reagent such as H25 or by evaporation ofthe solution and oxidation of the metallic component. The precipitationmay or may not be followed by reduction, for example with hydrogen underhigh temperature. The final catalyst will be in the form of distinctparticles which may be of any convenient size. For xed bed downflowoperations, spheres, pellets, or pills of from about l@ inch to A inchmajor dimension are preferred and for upow or uidized operations smallerparticles are preferred. Particles in the range of l0 to +16' mesh havebeen found to give particularly good results, indicating that thedistribution of material through a bed of that size particle isparticularly good.

The non-cracking base or the base having no cracking activity asdescribed herein may also be characterized as a non-acidic base. It isdesired that the base material used have no cracking activity as acatalyst although it may enhance the ability of hydrocarbons to crack byproviding a het dstended contact surface. Perhaps the best descriptionof the material is but an enumeration of a number of specific materialswhich may be used. Therefore, silica, alumina, magnesia, pnmice,kieselguhr, may be used and these may be steam deactivated or heatdeactivated prior to use. The silica, alumina, magnesia, and zirconiamay be naturally occurring or preferably syntheticallyprepared as byforming a hydrosol of the material and allowing it to gel either as acake or in the form of spheres, or powders which may later bc pellctedinto aggregates of whatever size is desired. Another suitable base maybe a carbonaceous base such as coke, coal, charcoal, etc. which materialcauses adsorption of molecules of hydrocarbon into the proximity of thecatalytic material without having cracking activity ol its own. Anothersuitable base may be a silica-alumina base, which` has good propertiesof surface area-andr strength, however, this silica-alumina base must besubstantially totally deactivated with respect to cracking activityprior to use in this process by steam deactivation, heat deactivation,treatment with ammonia or in a preferred method byincorporating analkali or alkaline earth material in the composite which destroys theacidic character of the silica-alumina and renders it inert with regardto cracking. It is understood that other bases which satisfy thequalifications set out herein may be employed within the broad scope ofthis invention.

Whether a base has catalytic cracking activity or not may best bedetermined by the character of the product resulting from it. In thepresent invention, using the catalysts specified in the manner specifiedthere will not be catalytic cracking as evidenced by the low yields ofgasoline and particularly by the occurence of dealkylation of highboiling kisoparallins to form waxes. A catalyst with cracking activitywill cause cleavage of these long, straight chain wax moleculeslsomewhere in the middle of the chain, resulting in the high yields ofgasoline that are characteristic of catalytic cracking, at the expenseofthe waxes and Wax forming molecules in the feed.

The destructive hydrogenation will be effected at a temperature of fromabout 750 F. to about850 F. since it has been found that below 750 F.there is little conversion whereas above 850 F. thermal crackingreactions are effected which cause the undesirable destruction of waxesand unsaturation of the recycle stock. It is thought that the cleavageof carbon-carbon bonds in this process is due to the tendency tohydrogenate two adjacent carbon atoms in a molecule and that thehydrogenation activity is the prime source in causing cleavage ratherthan thermal cracking activity. This analysis is more or lesssubstantiated by the fact that the catalytic material has no crackingactivity and yet cleavage of carbon-carbon bonds occurs at a temperaturebelow that at which thermal cracking should occur, however, it is notintended to limit this invention to the correctness of this analysis.

The process will be elected at a superatmospheric pressure in order toeiect the desired hydrogenation. Therefore, a hydrogen atmosphere willbe required in the reaction zone and this hydrogen atmosphere should beat a pressure of about 100 p. s. i. or higher and may be any pressure upto 10,000 p. s. i. or more when desired. It is contemplated that theprocess of this invention will be effected at ordinary space velocity,that is from about 0.25 to about volumes of charge per volume ofcatalyst present 'per hour, however, it is to be borne in mind that thespace velocity may be varied greatly and in some cases it may bevsufficiently high so that a higher temperature than the preferredtemperature described above may be used. The excessive equipmentrequirements for such high space velocity are such that only underspecial circumstances would they ever be used and under thosecircumstances of course a higher operating temperature will accordinglybe used.

The process will preferably include aregeneration cycle since a certainamount of coke formation will occur in the catalyst bed, however, theregeneration is not conv templated to be of thesame magnitude as in aconventional crackingoperation. For example, the process of thisinvention may function for several weeks or longer before regenerationof the catalyst is required after which a short regeneration period, forexample 1 or 2 days or less, may be required, after which anotheroperating period of several weeks may be used. Therefore, the preferredmethod of effecting the present process is as a fixed bed of catalystthrough which the charge stock is passed in either an upward or downwarddirection with intermittent periods of regeneration and this method ispreferred inasmuch as it represents the cheapest type of plant to buildand therefore the most desirable when the nature of the process permits.It is not intended, how-f ever, to limit this invention to a fixed bedoperation since a iixed iluidized bed, a uidized bed with cyclictransfer of catalyst from the reaction zone to the regeneration zone andback to the reaction zone or a moving bed process wherein a slowlydescending catalyst bed discharges from the reaction zone into aregeneration zone and the regenerated catalytic material is transportedto and deposited on the top of the catalyst bed in the reaction zoneafter suitable treatment with regeneration gases may be used.

The regeneration cycle must be controlled so that the heat ofregeneration does not destroy the catalytic activity of thehydrogenation catalyst employed and the maximum allowable heat willdepend upon the particular catalytic material used. The temperature ofregeneration must also be sufficiently low so as to not fuse the basematerial and this again will depend upon the particular base materialused. Ordinarily regeneration temperatures will not exceed 1400 F. andthey may be maintained below the maximum temperature bylimiting theamount of oxygen in the regeneration gas or by blending cooling gaseswith' the regeneration gas prior to introduction into the're-vgeneration zone.

The light lubricating oil fraction from the virgin crude taken from theoriginal fractionator in this process iS' blended with the lightlubricating oil from the synthetic crude produced in the destructivehydrogenation zone which will hereinafter be referred to as syntheticlight lubricating oil and the resultant blend is passed into ahydrogenation zone wherein unsaturated molecules contained in thesefractions are hydrogenated. The hydro-v genation of the lubricating oilfraction improves the lubricating oil by making it more stable and atthe same' time it substantially improves the quality of the valuable waxconstituents contained therein by lowering the solidiiication point andimproving its color thereby making it white 'and crisp instead of -brownand tacky. Whereas:

conventional processes for the manufacture of lubricating oil requiresolvent extraction steps to remove the aromatic compounds from the oils,the hydrogenationstep of this invention not only improves the oils ashere-` inbefore described but also eliminates the need for a solventextraction step in most cases by converting the. The hyaromaticmolecules tonaphthenic molecules. drogenation step also produces a lightcolored oil containing fewv if any foreign color bodies and therebyclimi-Q ess properly operatedc'osts less than the clay treating and italso improves the yield since the beneficial effect of af clay treatingprocess is due to a removal of material while in the hydrogenationprocess the improvement is due to a change in its characteristics.

Therefore, the process of this invention includes passing the combinedstream of virgin light lubricating oil" and synthetic light lubricatingoil into a hydrogenation' zone wherein this stream is contacted with ahydrogenating catalyst at hydrogenating conditions. The hydrogenatingcatalyst may be any of those commonly used such as metals of group VIII,the left hand column of group VII, the left hand column of group VI, andthe left hand column of group V and these may be used in the form of thepure metal or suitable compounds thereof-such as their oxides,"sulfides,halides, etc. The hydrogenating components may also be used incombination and particularly desirable combinations are those containingmetal components from the left hand column of group VI and from the irongroup such as cobalt-molybdenum, chrominut-nickel, tungsten-iron, etc.The catalytic material' 1s preferably disposed upon a base or carriermaterial v This latter savings has the double adwhich supports thecatalyst in distended surface condition andv may promote the reaction byinducing a catalytic etect of its own. Some of the preferred carriermaterials include silica, alumina, zirconia, magnesia, and arepreferably synthetically prepared and may be used in combination suchas` combinations of silica-alumina, silica-zirconia, boria-alumina, etc.The above materials may be synthetically prepared or naturally occurringwhen found as material such as kieselguhr, diatomaceous earth,montmorillonite clay, pumice, and magnesite, etc. Other suitablesupports may be of the carbonaccous type and include larnpblack, coke,brown coal, activated charcoal, boneblacli, etc. Particularly preferredhydrogenation catalysts include nickel supported on natural or synTthetic silica, cobalt or molybdenum supported on alumina, platinumsupported on alumina and chromium supported on alumina. When employingan alumina support it is frequently desirable to stabilize it with asmall quantity of silica.

The hydrogenation zone will effect the desired hydrogenation reactionsat a temperature of from about 100 F. toabout 500 F. and at a pressureof from about 100 p, s. i. to about 15,000 p. s. i. or more. Thereshould be suicient contact time to permit the reactions to occur and thecontact time will be regulated by the characteristics of the chargestock and the other operating conditions. Preferably, a liquid hourlyspace velocity of from about 0.25 to about 25 volumes of oil per volumeof catalyst per hour will be employed and the contacting of the oil bycatalyst will be effected in the presence of hydrogen. The reactions arepreferably effected in the presence of a fixed bed of catalystparticles, however, a fixed fluidized bed, tluidized bed, moving bed orslurry may be employed as hereinbefore `described when such a processwould be advantageous.

The hydrogenated light lubricating oil fraction as it cornes from thehydrogenation zone must be further treated in order to prepare it into asuitable material for lubricating. The light lubricating oil fractioncontains wax and possibly resin and this material must be removed togive oil the proper qualities of viscosity and pour point. Many meansare available for removing wax from oils and any of these are consideredas within the broad scope of this invention. Wax may be removed bydisplacing it from solution by treatment with proplane which material.dissolves in the oil fraction to displace the -wax and may be laterreadily separated from the. oil since it has such a `substantiallydifferent boiling point than the fraction in which it is dissolved.Propane displacement may also be used as the means of deasphalting andderesining the oil. In conventional processes a lubricating oil must bedeasphalted, dewaxed, deresined, solvent extracted and clay treated inorder to take out the various heavy or undesirable fractions, and toremove aromatic hydrocarbons which destroy the lubricating qualities andto improve the color of the fraction. The present process produces anoil with no asphalt, very little resin and readily removable wax whichis high quality. The process of this invention avoids the necessity of'solvent extraction and a clay treatment as hereinbeforeA described indetail.

The preferred method of treating the lubricating oil fraction` comingfrom thehydrogenation zone is to blend it with a, solvent or a mixtureof solvents which dissolve the wax. material and which, upon cooling,precipitate it as a separate solid phase. Suitable solvents includetoluene, benzene, acetone, methylethyl ketone, furfuryl,

As inrthe particular ex-v.

8 200 F. while the initial boiling point of the lubricating oil fractionis in the range of 600 F. The wax may also be removed by displacementfrom solution by propane in which case the boiling point differencebetween the oil and the purifying agent is even greater.

This invention may be more readily explained with reference to theaccompanying drawing which shows one embodiment of this invention and isintended to be illustrative of rather than limiting upon its broadscope.

Referring to the drawing the charge stock to the process, which in thiscase will be considered a crude oil, enters through line 1 into theintermediate portion of fractionator 2 wherein it` is separated byconventional means into a light hydrocarbon phase passing from the topof fractionator 2 through line 3, which light hydrocarbon phase containsall of the normally gaseous hydrocarbons as well as gasoline, kerosene,naphtha and gas oil; a light lubricating oil fraction which passesthrough line 4 and which contains material boiling roughly from about600 F. to about 950 F. and a bottoms fraction passing through line 5which contains material boiling roughly in excess of 950 F. It is ofcourse realized that these boiling ranges may be altered by operatingthe fractionation column differently and any desired fraction can beobtained as the seasonal demands or particular specifications dictate.The light hydrocarbons passing through line 3 are passed to otherprocesses while the bottoms product passing through line 5 is passedlargely into line 6, commingled with hydrogen-containing gas from line 7and the resultant mixture of bottoms and hydrogen gas passes intoconversion zone 9 via line 3. ln conversion Zone 9 the hereinbeforedescribed reactions occur as a result of the contact of the mixture ofhydrogen and bottoms with a catalytic material comprising a metalcomponent from the left hand column of group V and an iron groupcomponent preferably disposed upon a base having no cracking activity.The resultant material passes through line 10 into gas separator li andthe normally gaseous phase consisting largely of hydrogen, is separatedfrom the normally liquid phase, which is known as the synthetic crude.The normally gaseous phase passes through line 12 and is commingled withthe incoming hydrogen in line 7 or a portion of it may be vented throughmeans not shown. The normally liquid portion, or the synthetic crude,passes through line 13 into an intermediate portion of fractionator ld.

Fractionator le serves roughly the same purpose as fractionator 2 inthat it separates the synthetic crude entering through line 13 into alight hydrocarbon fraction passing through line 15 from the top offractionator 14, a synthetic light lubricating oil fraction passingthrough. line i6 from an intermediate portion of the fractionator and asynthetic bottoms fraction passing through line 17 from the lowerportion of the fractionator. The light hydrocarbon from line 15 may becommingled with that from the beforementioned line 3 and passed towhatever processing zone is used. The synthetic bottoms fraction passingthrough line 17 is preferably commingled with the virgin bottomsfraction passing through line 5 and returned via lines 6 and S toconversion Zone 9. The synthetic bottoms fraction may, however7 byoperation of valves 18 and 19 to regulate the flow through lines 20 and21, be passed into a dewaxing and deresining zone which will bedescribed in more detail hereinafter.

The synthetic light lubricating oil passing through line 16 iscommingled with the virgin light lubricating oil in line and theresultant blend passes through line lo into line 22 wherein it iscommingled with hydrogen from line` 23. The mixture of hydrogen andlight lubricating oil passes into a hydrogenation zone 24 wherein thehercinbefore described hydrogenation reactions are elfected in thepresence. of a hydrogenating catalyst such as for example, platinummetal distended on alumina- The resultant material passing fromhydrogenation zone 24 through line 25 is a saturated, stable,substantially sulfur and nitrogen-free material boiling in the range oflight lubricating oil. This material passes through line 2S to gasseparator 26 wherein itis separa-ted into a normally gaseous hydrogenrich phase which passes through line 27 and commingles with thebeforementioned hydrogen in line 23 and a liquid lubricating oilfraction which passes through line 28 into dewaxing zone 29.

ln this embodiment the dewaxing zone functions by commingling the entirefraction with a solvent passing into the dewaxing zone by way of line 30which dissolves wax from the fraction, which wax is subsequentlyprecipitated as a solid and i'lltered from the liquid material. The waxpasses from the dewaxing zone through line 31 while the dewaxed lightlubricating oil and solvent pass through line 32 into a solventseparator 33. In solvent separator 33 the relatively simplefractionation is effected to separate the solvent material from thelubricating oil and the resultant separated solvent passes through line34 and commingles with the incoming solvent in line 30. From the bottomof solvent separator 33 the desired light lubricating oil passes throughline 35 as product.

By suitably regulating the temperature and conditions of the variousfractionation and reaction zones the light lubricating oil in line 35may be of any grade desired such as S. A. E. for example. The lightlubricating oil may be raised to different or higher grade lubrieatingoils by blending it with heavier lubricating oils which may be obtainedas hereinafter described. This blending stock may be passed into contactwith the product as it is formed by way of line 36 to form an ultimateproduct of whatever grade is desired.

The hereinbefore described synthetic bottoms fraction may, throughsuitable setting of valves 1S and 19, be passed with the virgin bottomsfraction from line 5 or into dewaxing and deresining zone 37 wherein itis treated with solvent entering by way of line 38 in a manner similarto dewaxing zone 29. The resultant wax material is withdrawn from line39 while the dewaxed andderesined bottoms fraction which is mixed withsolvent is passed through line 40 into solvent separator 41 wherein thesolvent is separated and passed overhead through line 42 and returned tosolvent line 38 while the dewaxed and deresined heavy lubricating oilpasses through line 43. The material in line 43 may be withdrawn byopening valve 44 and withdrawing the heavy lubricating oil product or itmay be passed, by opening valve 45 into the beforementioned line 36 toblend it with the light lubricating oil product as hereinbeforedescribed. Although not shown, suitable valves and lines may be employedso that the virgin bottoms matenial from line 5 may be passed directlyto dewaxing and deresining zone 37, or alternatively, a blend of boththe virgin and synthetic material may be charged to zone 37. Ashereinbefore stated, it must be realized that the gure herein describedis intended to illustrate merely one preferred embodiment of thisinvention and is intended to include the ordinary and customarymodications which may be made within the broad scope of this invention.

From the foregoing it may readily be seen that the process of thisinvention provides a means of producing high yields of lubricating oilfrom a fraction containing little or no lubricating oil and thelubricating oil 10 resulting from this process is superior to the virginmaten rial obtained by distillation. The process similarly increases theyield and quality of the extremely valuable wax by-product obtained fromthe processing of oils to produce light lubricating oils.

We claim as our invention:

l. The method for producing lubricating oil which comprises separating apetroleum material into at least a light lubricating oil fraction havingan end boiling point above about 600 F. and a bottoms fraction having anend boiling point above about 900 F., passing at least a portion of saidbottoms fraction into contact with a catalyst comprising a componentcontaining metal from the left hand column of group VI and an iron groupmetal component at a .temperature of from about 750 F. to about 850 F.and a hydrogen pressure in excess of about p. s. i., separating theresultant converted material into a synthetic light lubricating oilfraction and a synthetic bottoms fraction, commingling the resultantsynthetic light lubricating oil fraction with the first-mentioned lightlubricating oil fraction and passing the resultant mixture with hydrogeninto contact with a hydrogenating catalyst at a temperature of fromabout 100 to about 500 F., and dewaxing the resultant hydrogenated lightlubricating oil fraction to produce the aforesaid lubricating oil.

2. The process of claim l further characterized in that said catalystcomprising a component containing a metal from the left hand column ofgroup VI and an iron group metal component is disposed on a carrierhaving no cracking activity.

3. The process of claim l further characterized in that the catalystcomprising a component containing a metal from the left hand column ofgroup VI and an iron group metal component. is subjected to periodicregeneration.

4. The process of claim l further characterized in that the syntheticbottoms fraction is at least partially dewaxed and blended with thelight lubricating oil product.

5. A process for producing lubricating oil from a Wide boiling rangehydrocarbon material which comprises fractionating said hydrocarbonmaterial and separating therefrom a light lubricating oil fractionboiling between about 600 and about 950 F. and a bottoms fraction havingan end boiling point above about 950 F., con- Y tacting at least aportion of said bottoms fraction, at a temperature of from about 750 toabout 850 F. and a hydrogen pressure in excess of about 100 p. s. i.,with a catalyst comprising a metal from the left-hand column of group VIof the periodic table and an iron group metal, separating a syntheticlight lubricating oil fraction from the resultant products andcommingling the same with the first-mentioned light lubricating oilfraction, subjecting the resultant mixture to catalytic hydrogenation ata temperature of from about 100 to about 500 F., and dewaxing thehydrogenated light lubricating oil thus formed.

References Cited in the le of this patent UNITED STATES PATENTS2,360,622 Roetheli Oct. 17, 1944 2,554,282 Voorhies May 22, 19512,660,552 Blanding Nov. 24, 1955 2,700,015 Joyce Jan. 18, 1955

1. THE METHOD FOR PRODUCING LUBRICATING OIL WHICH COMPRISES SEPARATING APETROLEUM MATERIAL INTO AT LEAST A LIGHT LUBRICATING OIL FRACTION HAVINGAN END BOILING POINT ABOVE ABOUT 600*F. AND A BOTTOMS FRACTION HAVING ANEND BOILING POINT ABOVE ABOUT 900*F., PASSING AT LEAST A PORTION OF SAIDBOTTOMS FRACTION INTO CONTACT WITH A CATALYST COMPRISING A COMPONENTCONTAINING METAL FROM THE LEFT HAND COLUMN OF GROUP VI AND AN IRON GROUPMETAL COMPONENT AT A TEMPERATURE OF FROM ABOUT 750*F. TO ABOUT 850*F.AND A HYDROGEN PRESSURE IN EXCESS OF ABOUT 100 P.S.I., SEPARATING THERESULTANT CONVERTED MATERIAL INTO A SYNTHETIC LIGHT LUBRICATING OILFRACTION AND A SYNTHETIC BOTTOMS FRACTION, COMMINGLING THE RESULTANTSYNTHETIC LIGHT LUBRICATING OIL FRACTION WITH THE FIRST-MENTIONED LIGHTLUBRICATING OIL FRACTION AND PASSING THE RESULTANT MIXTURE WITHHYDROGENINTO CONTACT WITH A HYDROGENATING CATALYST AT A TEMPERATURE OFFROM ABOUT 100* TO ABOUT 500*F., AND DEWAXING THE RESULTANT HYDROGENATEDLIGHT LUBRICATING OIL FRACTION TO PRODUCE THE AFOREAND LUBRICATING OIL.